Manufacture of bicarbonate of soda



(No Model.) 7 2 Sheets-Sheet 1.

E. CAREY, H. GASKELL, Jr..- & F HURTER. MANUFAOTURE 0F BIGARBONATE 01E SODA. No. 276,990. Patented May 1, 1883.

N- FETERS MLhMgr-vlur, Wlahiughn, I) C.

(No Model.)

2 Sheets-Sheet 2,

E. CAREY, H. GASKELL, Jr., 82; F. HURTER.

M 0 9 9 6 7 Z 0 N PatentedtMa-y 1, 18.83.

MMW WHU a. PETERS. mo ulhc npbm Wnhingmm. n c

UNITED ST TES PATE T A OF ICE. A

EUSTAGE c EEY, HQLBROOK GAsKELt, JR, AND FERDINAND HUETEE, F wIDNEs, COUNTY or LANCASTER, ENGLAND.

MANUFACTURE OF BICARBONATE OF SODA.

SPECIFICATION forming part of Letters iatent No; 276,990, dated May 1, 1883.,

Application filed July 24, 1882. (NomodeL) Patented in England November 16, 1881, No. 5,024.

To all whom it may concern.-

Be it known that we, EUSTAGE CAREY, H01.- BROOK GAsK LL, J r., subjects of the Queen of Great Britain,and FERDINAND HURTER, Ph. D., a citizen of Switzerland, and residing respectively at Widnes, in the county of Lancaster, England,'alkali manufacturers, have invented. certain Improvements in the Manufacture of Bicarbonate of Soda, (for which we have obtained a patent inGreat Britain, No. 5,024, dated November 16,1881,) of which the following is a specification.

This invention relates to the manufacture of bicarbonate of soda from that form of crystallized carbonate of soda commonly known as salts, these-me being obtained during the f'salting down? or evaporation by heat of solutions of carbonate of soda. These salts are, essentially, a monoh yd rated carbonate of soda, although the degree of hydration may vary slightly, according to the temperature and other conditions in the salting-down operation.

The invention consists in subjecting the.

said salts with agitation to the action of car bonic acid and in regulating or controlling the (amount of moisturelin the compound, removing any excess, and supplying any deficiency as may be required, whereby a uniform drybicarbonate may be obtained from said salts agitation; but in this process there isnot only no regulation or control of the supply of moistare to one equivalent, so as toobtain a dry bicarbonate, but, on thecontrary, water is to be added whenever the amount thereof is less than half the weight of the carbonate, so the moist article.

bicarbonate produced will necessarily be a The process is, however, mainly designed forthe -purification of soda. The

[ordinary method of preparing the carbonate by carbonating soda crystals results in the the amount of waterot' crystallization,) which and often loss.

The invention further comprises a new apparatus, which is or may be used in carrying the improved process into effect.

In carrying out our invention we find it adillustrated in side elevation, end view, andplan, respectively, in Figs. 1, 2, and 3 of the accompanying drawings. The iron cylinder A, of convenient size, is capable of being rotated upon a horizontal axis. lVe find it convenient to make the cylinder A of about eight feet in length by five and a half feet in diameter. A cylinder of that size will hold a charge of about thirty hundred-weight of salts and produces therefrom about forty'hundred-weight of bicarbonate. The cylinder A is provided with hollow trunnions or axes supported by and capable of turning in bearings a, carried by aone end of the cylinder is used for admitting carbonic-acid gas, and that at the. other end is used for permitting the exit, when desirable, of any superfluous moistureflthe hollow axles are continued into the interior of the cylinder and deflected upward, as shown at b in Fig. 1, for the purpose of avoiding the lodgment stoppage ofthe free passage of the gas into or from the cylinder. I I h We find it advisable to have apertures at e e in the cylinder A and exit-pipe C, respectively, which can be closed air-tight in any convenessary, the part of the exitpipe 0 which is inside the cylinder A may be cleaned easily and freed from dust, which is sometimes deposited there. Outside the cylinder A the exit-pipe (J is carried upward at 0 to asuita ble height, and is then returned down ward an d connected by the branch 0 with the pipe 0, by which the carbonic acid enters at the other end of the cylinder A. We find that when the pipe G is carried upward at 0 about thirty feet the difference of temperature, and consequently production of a moist bicarbonate, (owing to has to be dried for use at considerable trouble suitable frame-work. The hollowaxis at the vantageous to employ an apparatussuch as is V therein of solid material and the consequent ient manner, and through which, when nee 7 a ,eeo

' such that a circulation of gas can be commenced and maintained when desired through the pipe 0, whereby the moisture which escapes from the salts during the process is conveyed' away from the cylinder A and is condensed in the pipes, and may be collected and run off through a lute, 00, or otherwise, the surplus carbonic-acid gas returning to the cylinder by the branch ci. Fig. 4 shows a lute drawn to a larger scale. If at any time this circulation does not commence when desired, we open for afew moments a tap provided for the purpose at the bottom of the downcast pipe above the lute.

which our invention may be performed, we now proceed to describe the method of working which we find to give the best results.

The charge of salt introduced in the cylinder A is closed and madeto revolve slowly through theintervention of a pulley and spurgearing G, driven by any suitable motor. We find from two or six revolutions per minute are sufficient. Carbonic-acid gas is turned on or admitted into the interior of the cylinder A by the pipe 3 The temperature of salts or carbonate of soda rises, and the carbonic-acid gas is rapidly absorbed by the charge. The progress of the operation may be ascertained by withdrawing and testing a sample from time to time. We'find, however, that with a regular and sufficient supply of pure or almost pure carbonic acid the operation is so uniform that after a short experience sampling and testing are unnecessary, the state of the carbonating of time that-the operation has been in progress.

When absorption decreases the temperature falls, and we find in practice that about five or six hours are sufficient to complete the operation, and that at the end of two'or three hours,

or at the expiration of about one-third of the time necessary to complete the operation, it is advisable to commence drawing off the superabundant moisture. The operation will then proceed satisfactorily, and the resulting bicarbonate will in due time be completely finished, and will be found dry and of great purity and ready, when cold, for immediate grinding and dressing.

' The details of the foregoing operation will vary with circumstances, and will depend upon the character of the salts and the amount of moisture they contain. Ifand when the salts are too dry, or become so during the operation, it is necessary to add water, this we prefer to do by adding steam tothe carbonic acid. We

v By doing this circulation is at once set up in the pipe 0, and when commenced pass the carbonic acid, before it reaches the inlet-pipe y, to the cylinder A through a small tower, D,contiguous to the cylinder, and filled with coke or other suitable material, into which the requisite quantity of steam is passed. This causes the carbonic acid to enter the cylinder A saturated or sufficiently saturated with moisture for the purpose. We find a very small tower sufficient. A cylinder three feet diameter and four or five feet high is sufiicient for the purpose. Water may also be added to the salts by injecting a fine spray of water into the cylinder A. If and when dilute carbonic acid is employed-such as that resulting from the combustion of anthracite or coke-where an inert gas or gases are present, it is advisable to have two or more cylinders A connected together and so arranged that theinert gas or gases may be permitted to escape without undue loss of carbonic acid. We effect this by having a series of two or more cylinders of convenient size, and passing the exit-gas from one cylinder into the next, and so on to the last, the inert gas or gases being allowed to escape freely from the last cylinder of the series. Between each of the cylinders a gasdrying apparatus and a gas-moistening apparatus may be placed, and the exit gas or gases from the one cylinder dried or moistened, as required, on its or their way to the next cylin der. The gas-pipes can be so arranged, asis well understood, that any one cylinder of the series can be isolated for filling or emptying or other purpose. Fig. 5 represents in plan an arrangementof apparatus for this purpose. According to this arrangement three oylinders, A A A are employed,which are essentially of the same construction as represented by Figs. 1, 2, and 3. Each of them is capable of revolving independently of the others, suitable gearing, Gr, being provided for such purpose. The plan shows one method of connecting three cylinders so that any oneof them may beisolated, and

this method can easily be adapted to any number' of such cylinders. The carbonic-acid gas from any source enters the distributing apparatus H by the central pipe, y. This distributin g apparatus consists of a cylindrical vessel, through the bottom of which pass water-tight the central inlet-pipe, y, and three pairs of pipes arranged in a circle round this inlet-pipe, each pair being connected with the inlet and outlet of one of the cylinders A A A, respectively. The cylindrical vessel H contains a sufficient; depth of water-to resist the press ure or suction, if any, of the gas. The open ends of the pipes reach above the level of the water a distance at least equal to the depth of the water in the vessel. Movable bent pipes are provided to slip over and connect any one of those pipes with any other.

The drawings represent the whole of the three cylinders A A. A connected in the followingmanner: The central inlet-pipe, y, is connected to the pipe 3 by a movable arm, 0 so that the carbonic acid may pass to the moistcnin g apparatus D and enter into the cylinder A. The gas passing out by the pipe which is of sufficient length to cool the gas and condense excess of moisture, or, if not of suflicient length, may be carried upward and downward asuitable distance for the purpose) returns to the distributing apparatusH, where pipe-c is connected to pipe 3 by a movable arm, 0 The gas thus is caused to pass to the moistening apparatus D from there to the cylinder A and returns by the pipe to the distribut'er, where the pipec is connected to the pipe 3 by another movable arm. The gas finally passes through the moistening apparatusl) and cylinder A returns once more to thedistributer H bypipe c and thence it. may be al-. lowed toescape by the ring-pipe z and outlet 2 If an y water condenses in any of the pipes,

it is allowed to escape through a lute similar to that represented in Fig. 4. If. any of the moistenin g apparatus is not required for moistening purposes, the steam is not turned on thereto. Fig. 6 shows a section of the distributin g apparatus. The drawing shows pipe 0 connected by a movable arm, 0 to the pipe 5 z, forming a complete ring round the distributing apparatus H. Thisringshaped pipe has four branches,z z Three of these branches, 2, are placed opposite'the termini of the pipes c c cfirespectively, and serve to connect, by means of the arms 0 any one oftbesepipes to this ring 2. The fourth branch, a of the ring zis connected either to a chimney or an exhauster, which removes the inert gases. All these branches of the pipe 2 not in actual use a are covered with. a lid, asat 2 All connections are luted with water, asis wellunderstood.

Having now described the nature ofour invention and the means whereby we carry it intoeffect, we desire to point out that we do not confine ourselves to the above-described or to any particular form of apparatus; but that What we claim as novel is y 1. The manufacture of bicarbonate of soda by the employment and. treatment, as hereinbefor e described, of what have been hereinbefore referredto as salts, and hereinbefore defined, by subjecting said salts to the action ofcarbonic-acid gas, the salts being mechanically agitated and the superabundant heat being removed, the moisturegenerated being ing pipesconnected with said cylinder, sub-. 'stantially as described. l

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

EUSTAGE CAREY.

HOLBROOK GASKELL, JR. FERDINAND HURTER. V

Witnesses:

FRANK GASKELL, Woolton Wood, Liverpool.

ALEXANDER WALKER,

Widnes, County of Lancaster, Great Britain. 

